16 ms·
> Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically
by Aurornis 1y ago
> Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better.
EV motors are already lightweight. The electric motor in a vehicle like a Tesla Model 3 already weighs less than you do. Reducing that one component by 75% would be a weight savings equivalent to about a half of a passenger.
Not a significant efficiency improvement for vehicles that weigh over 3000lbs (or double that for many EVs).
Every little bit helps, but this isn’t a game changer.
- catapart 1y agoIt drops a buck fifty per motor. That IS a game changer. It can make cars cheaper, or longer range, or faster, or any number of other designs based on what the manufacturer is looking for. But to OP's point about flight - stacking 6 Tesla motors is not an option. Stacking 6 of these YASA motors? Much less weight.
- Aurornis 1y ago> It drops a buck fifty per motor. That IS a game changer. You’re reading their marketing material. You have to think of this like all of those PR releases you’ve seen over the years about new battery technology that is 4X smaller or new hard drive tech that is 10X more efficient. The real world improvements aren’t going to be as big as their one lab test. A Model 3 motor is already well under 150lbs, unless you start including ancillaries like the inverter and power transmission parts. They’re not dropping “a buck fifty” from typical EV motors.
- catapart 1y agoI'm not reading anyone's marketing material. If you want to dispute the shipping weight, feel free to correct this website whom I assume charges for shipping based on weight [0]. I'm sure they'd love to know they have it wrong. According to purchasable equipment, the Model 3 engines weight ~175 lbs. If that's wrong, that's on them for claiming it. Subtract 28 lbs from that and you're at 147 lbs. That is very close to 150 lbs. [0] https://evshop.eu/en/electric-motors/295-tesla-model-3-drive-unit-with-controller.html https://evshop.eu/en/electric-motors/295-tesla-model-3-drive...
- Aurornis 1y agoThat’s a drive unit, which is more than the motor. Read the description: > This kit includes the Tesla motor, inverter, gear box, power cables and drive shafts. Drive shafts, gearbox, power cables, inverter. Also includes the mounts, which is likely not factored into the lab calculations for this marketing material. You cannot drop 150lbs from the Model 3 motor because it doesn’t even weigh 150lbs.
- catapart 1y agoYou're missing the forest for the trees. Dropping 10 lbs per motor is HUGE. Dropping 30 is amazing. Whatever is dropped, it's significant. Pretend that it isn't all you want, but anyone doing production work knows how important this is. I'm happy to compare apples to apples when we can do that, and if you want me to say I was wrong about the Tesla motor size I'm happy to say that I was just going by what was available on the internet and skipped the details. But I did so in service of a point which you still haven't actually engaged with beyond "Nu uh!".
- Aurornis 1y ago> Dropping 10 lbs per motor is HUGE. Auto makers could drop 10lbs, 100lbs or even more from every EV right now by choosing more expensive materials, more expensive manufacturing processes, or simply cutting back on amenities. 10lbs is not significant in the grand scheme of things. The real question is how much it costs, what are the tradeoffs, and how practical is it. > But I did so in service of a point which you still haven't actually engaged with beyond "Nu uh!". That’s not a fair take on what I’ve been posting at all. I said every little bit helps, but pointed out that motor sizes are already small.l
- catapart 1y ago10 lbs per motor in an aircraft is huge. And the fact that they can do it WITHOUT having to use more expensive materials or manufacturing or amenities is the thing that is huge about it. It's a fair take on your responses because talking about a SINGLE motor is missing the point. You're not engaging with the actual point that OP made, you're trying to dispute OP by engaging in your own point about what difference this would make in single-motor cars, instead of what difference it will make in general.
- elihu 1y agoNah, the main thing is that electric motors are already far better than they need to be -- even assuming the claims are all true, it would only make a small difference. Shaving a couple percent off the total vehicle weight would still be a very good thing, but improving batter energy density by 10% or so would be a bigger deal for most EVs. There might be some niche applications where the battery weight isn't the biggest issue -- like very short-range, light-weight vehicles that need to have enormous amounts of power for some reason. I could see motors like this being used in power tools if they can be scaled down. A light-weight plug-in electric chainsaw would be pretty awesome.
- nandomrumber 1y ago> A light-weight plug-in electric chainsaw would be pretty awesome. These already exist, in both plug-in and cordless / battery powered.
- elihu 1y agoSmall wimpy ones are widely available. I'd love to have an electric chainsaw that runs on 220v and has a respectably long bar, but those don't seem to be available in the US as far as I can tell. At 30 amps and 220 volts, that would be about 8 horsepower. I think most motors that size rated for that much continuous power would be rather heavy.
- whamlastxmas 1y agoRange in EVs is impacted very little by weight
- gogusrl 1y agoExactly. I was very surprised to find out a fully loaded 40 ton electric truck only uses ~100kw / 100km ( https://www.youtube.com/@electrictrucker https://www.youtube.com/@electrictrucker ) when my 2 ton Volvo averages 20-22kw/100km on road trips.
- deleted 1y ago[deleted]
- hinkley 1y agoSuperfastmatt did a test recently where he proved to himself that the front area of the vehicle and trailer is the dominant factor on mileage, not the weight towed or friction. For a guy trying to drive 300 mph though maybe he should have been able to do that with math instead of sketchy road tests.
- ninalanyon 1y agokWh not kW.
- nandomrumber 1y agoNewton’s first law helps out a lot here.
- hinkley 1y agoLooks like it’s about 45 kg for a Tesla and 13 kg for this one. It at twice the horsepower. So maybe 8-10kg for a down rated model. IIRC, axial motors need their diameter to retain their efficiency advantage so a down rated one would likely be lighter but close to the same external dimensions. But that’s still a lot less rotating mass, and might make multiple motors attractive again.
- Lio 1y agoNot a game changer but I wonder if ligher motors allow you to do things like have one motor per drive wheel, removing the need for differential gearboxes? Then you can do clever things with traction control without having to use the ABS system to brake the drive wheels. Or dramatically change the turning circle on big cars and vans. Maybe even reduce the size and weight of the braking system by taking on some of that role. All for the same weight budget.
- GenerWork 1y agoI believe that some EVs already have 1 motor per wheel such as the top of the line Rivians that are advertised as quad motor.
- jjtheblunt 1y agohttps://www.mbusa.com/en/vehicles/model/g-class/suv/g580w4e#key-features https://www.mbusa.com/en/vehicles/model/g-class/suv/g580w4e#... has four electric motors
- mrguyorama 1y agoPutting the motors in the wheel is bad for a separate reason: Unsprung weight. Every ounce you have in the hubs that don't float on the suspension reduces certain suspension attributes. You end up with a crappier ride and poor performance.
- duskwuff 1y agoIf the motors are light enough, though, that might be acceptable... especially if they can make an even smaller version for that application. (You probably don't need 750 kW on each wheel - even for a supercar that'd be excessive.)
- fragmede 1y agofwiw four of those electric motors is approximately 4,000 hp. You won't get better 0-60 times with that though, at that point, you're limited by the tires' physical limitations. So at best you could get down to a ~2.2 second 0-60 mph time with regular tires, and then after that, you'd need race sticky tires in order to go faster. Unless you used the motors to power fans instead, then you could use that for downforce and propulsion, and get well belown 2 seconds, theoretically. F1 cars with fans to run them upsidedown but with remote drivers for their safety maybe?
- lucisferre 1y agoI would expect that lighter motor components would potentially allow weight reduction in load bearing components. Not an advantage for SUV-type cars, but for light and ultralight vehicles it could add up to more weight saving and longer ranges.
- hinkley 1y agoYou still have to handle the torque of the smaller motor. 30kg is maybe 2% of the vehicle weight.
- baxuz 1y agoThe difference is when you take into consideration rotating mass, and the distribution between the stator and rotor.
- Empact 1y agoThis, or a miniaturized version thereof could change the game for light electric vehicles - imagine an electric motorcycle that weighs substantially more like an electric bicycle. Right now it takes about 10-15lbs of motor to produce a 3KW motor for an electric bike, this motor is about 10 times that in power density afaict. The Livewire electric motorcycles use something like 100-200 lbs of motor to produce 1/4 as much power, 75kw, so that’s an improvement of 8-16x.
- mperham 1y agoThere’s no area in the world that allows e-bikes with more than 750w motors. A 3kw motor is illegal (cf Surron), unless you are talking about an e-moped requiring registration.
- rconti 1y agoOkay, but is it difficult to extrapolate the weight saving benefits of a "legal" power e-bike motor?
- MadnessASAP 1y agoListen, your world may not allow you to sell an e-bike with a 1000hp motor on it. But my world allows me to put a 1000hp motor on an e-bike and not tell anyone. Now hold my beer...
- doubled112 1y agoThere's a difference. I've noticed that people seem to believe as long as they bought something it should be safe. If you're smart enough to build something, I have to hope you're at least smart enough to realize that there might be consequences. Take your beer back, I'm going for a rip next.
- usrusr 1y agoSo that you can flip over in an uncontrolled wheelie at an even lower fraction of the throttle? Even if there was infinite energy throughput (aka power) at zero mass, the main limiter for power per total system mass would still be the battery. In any practical setup, even in super short runtime designs, getting, say, twice the power would not all that dramatic a runtime hit if it was achieved by scaling the same motor technology and paying for the extra mass with a little battery capacity. Unless of course you want to actually use that power increase for any meaningful fraction of the runtime, then you'll obviously drain the battery fast. But a zero-mass power increase would not change that a lot either. Increasing power density (of the motor) just isn't worth much when it does not happen to coincide with an increase in efficiency (and then the battery mass saved for achieving the same range will quite literally outweigh the mass saved by a smaller engine for achieving the same power) The good news is that those striving for power density aren't really at liberty to completely ignore efficiency in the process because cooling is a key issue for them.
- deleted 1y ago[deleted]
- huijzer 1y agoExactly. Main problem is battery energy density. Cars can drive about 20 kilometers on 1 liter of gasoline. In comparison, Tesla's 4680 cells are at about 272-296 Wh/kg and CATL's Kirin Battery at about 255 Wh/kg. A bit efficient EV often uses 200 Wh/km, so for 1 kg of battery the electric vehicle can only reach 1-2 km. An order of magnitude difference. Theoretically, batteries could go to 1000 Wh/kg some day, which would mean about 5 km per 1 kg of battery assuming all else remains equal.
- cwmoore 1y agoOranges to apples so long as electron mass is fixed and reserve currencies fluctuate.
- mattlutze 1y agohttps://ev-database.org/cheatsheet/energy-consumption-electric-car https://ev-database.org/cheatsheet/energy-consumption-electr... The Model 3 manages < 140 Wh/km, and many seem to be under 150/160/170.
- murkt 1y agoThat’s still around 2 km per kg of batteries.
- dotancohen 1y agoI'm at 115,000 km, at 133 Wh/km since the last (inadvertent) trip reset. The previous one (for the life of the vehicle) was at a similar number. This is on a 2022 Long Range Model 3.
- deleted 1y ago[deleted]
- mattlutze 1y agoIf you're putting motors in wheels, lower weight means reducing the weight/capacity of adjacent systems. Lighter motors for mobile robots could also be cool.
- icedrift 1y agoFor EVs no but it's huge for flight if it could be scaled down. Paramotors and ultralight planes are on the verge of being competitive with gas they just need a bit more energy density per pound in the system.
- BiteCode_dev 1y agoThen for drones ?
- FireBeyond 1y ago> The electric motor in a vehicle like a Tesla Model 3 already weighs less than you do. Reducing that one component by 75% would be a weight savings equivalent to about a half of a passenger. Of which there can be two, or even three.
- ElijahLynn 1y agoNice observation that the weight isn't that much of a deal compared to batteries for electric vehicles! It does seem like with this advancement, and the size of these axial flux motors that maybe, all wheel drive vehicles will be the default. As well as sub 3 second acceleration, which can make vehicles safer, for example getting out of the way of an incoming object. Of course it could also make them less safe because that vast of acceleration is kind of dangerous. But I do wonder if the weight reduction (over 30%) of lithium sulfur batteries paired with these is really going to make a great recipe for all sorts of quiet, long lasting, powerful electric vehicles and robots!
- jesse__ 1y agoSomebody's probably already pointed this out, but in the case of motors, making them lighter can make a big difference. For example, by making the flywheel in a clutch lighter, you reduce the amount of torque it takes to spin the flywheel. Saving 10 pounds there is not a 10/3000lb difference.. it could be a huge percentage of total power output.
- londons_explore 1y agoTo be precise, the impact of mass inside the rotor of the motor is 2 * the mass * the rotor diameter / the wheel diameter * the drivetrain gear ratio. For a typical EV, I think that works out to a factor of around 2.
- narrator 1y agoMaybe this would be good for a personal quadcopter, however the batteries weight would probably make the motor weight savings unimportant.
- inasio 1y agoBasically Amdahl's law [0]. If optimizing for weight, go for the components that make up most of the weight first. [0] https://en.wikipedia.org/wiki/Amdahl%27s_law https://en.wikipedia.org/wiki/Amdahl%27s_law